Hi,
Based on the error message, the issue seems to be that you are not able to send/receive emails in Outlook?
For the error 0x8004210E, we usually suggest:
Temporarily disable antivirus software and anti-spam software
Use Web access to delete malformed e-mail messages
As you mentioned you have performed the steps above, I suggest you also try these two steps below:
1. In case the data file(.pst or .ost) is corrupted, please run Scanpst.exe to scan and repair the possible problems:
Outlook 2013
32-bit Windows C:\Program Files\Microsoft Office\Office15
64-bit Windows C:\Program Files (x86)\Microsoft Office\Office15
64-bit Outlook C:\Program Files\Microsoft Office\Office15
Click-to-Run C:\Program Files\Microsoft Office 15\root\office15
Outlook 2010
32-bit Windows C:\Program Files\Microsoft Office\Office14
64-bit Windows C:\Program Files (x86)\Microsoft Office\Office14
64-bit Outlook C:\Program Files\Microsoft Office\Office14
Outlook 2007
32-bit Windows C:\Program Files\Microsoft Office\Office12
64-bit Windows C:\Program Files (x86)\Microsoft Office\Office12
2. The send/receive settings may be corrupted, we can try to find the .srs file and rename it to .old, Outlook will generate a new one the next time it starts, check if the problem persists. The .srs file location is below:
C:\Users\username\AppData\Roaming\Microsoft\Outlook
I hope this is helpful.
Regards,
Melon Chen
TechNet Community Support